1. Field of the Invention
This invention has as its object a process of launching a capsule into space and a corresponding launching means.
2. Discussion of Prior Art
Below, the word "capsule" is to be taken in the broad sense of means containing any payload, this means being able to be launched into space and to be recovered on earth. The word therefore does not at all prejudice the form of this means nor the nature of the payload.
The invention finds a preferred application in the field of microgravity research.
The main problem which the microgravity research comes up against today is that of means to create the conditions of this microgravity: if simulation means, such as the free-fall turns or the parabolic flights by aircraft, are used, the duration of the experiment is limited (from several seconds to several tens of seconds) and insufficient to carry out complex experiments.
The use of sounding rockets makes it possible to reach several minutes and to recover the payload, but the cost is increased by it and in any case the duration is still insufficient for a large number of missions. Further, the carried weight is limited by the size of the existing sounding rockets and the recourse to larger vehicles would appreciably increase the costs while the duration would remain small.
The experimentation orbital flight therefore is the means best suited to this research, but it assumes that suitable flight opportunities are available.
To meet this requirement, many solutions have been proposed that can be classified in three categories:
the launching of recoverable capsules by existing vehicles, such as Chinese launcher CZ2, U.S. launchers SCOUT and SUPER SCOUT, European launcher ARIANE 4,
the development of small launchers whose main mission would be launching of payloads suited to microgravity, such as U.S. launcher PEGASUS launched from a bomber, or small powder launchers such as the LITTLE LEO launcher of the British firm ORDNANCE,
the flight shared in existing capsules for which the experimenter would entrust his equipment to the developer of the system which would assure the launching and the recovery. This is what is proposed by China, which has already made several flights carrying European, particularly French, experiments, and by the Soviet Union with the Photon capsule. This solution results in low costs, but provides only very little control of the operation and no technological benefit in matters of the capsule, or reentry or of orbital operations.
The main drawback of these various solutions is to require a specific flight which, even with a small launcher, is costly: by way of example, a SCOUT launching costs about 12 million dollars to place a load of 200 kg at 500 km of altitude. It does not seem that the planned light launchers will be much more economical, because the SCOUT launcher already broadly reuses the stages designed and produced for heavier launchers.
In regard to the shared flight, it comes up against a double drawback:
the geostationary transfer orbit which is used is poorly suited to the recovery of a capsule because it leads to very high heat fluxes at the reentry and therefore requires heavy heat protections; it can further involve a very large dispersion of the impact zone, making the recovery more difficult,
in spite of the sharing of the flight, the cost remains high for the microgravity payload, the transfer orbit being costly in energy; the carrying of this additional passenger is reflected necessarily by the passing to a more powerful version of the launcher.
The use of heavier orbital means, such as "SPACELAB" or "EURECA," is also possible but would be suitable particularly to confirmed experimental devices. Actually, to the high cost of carrying the experiment resulting from its integration in a complex unit is added the problem of periods which are very long at times between the selection of an experiment and the time when its results are available for analysis. These periods do not make it possible to establish an iterative process. Even when the large capacity offered by the space station is available, many experiments will have to be justified by a prequalification obtained with a less elaborate system.